1. Field of the Invention
The present invention relates to a semiconductor package, and more particularly, to a semiconductor package in which an adhesive force between an insulating metal substrate (IMS) and a molding member is improved and a method of fabricating the same.
2. Description of the Related Art
In a semiconductor power module package, a power semiconductor chip and a control semiconductor chip are integrated in one package. Semiconductor power devices include silicon-control rectifiers, power transistors, insulated-gate bipolar transistors (IGBTs), power regulators, inverters, and converters. Such power devices are operated at a high voltage of 30 to 1000V or above unlike a low voltage device such as memory devices, and thus, require a high heat dissipation capability and an insulation capability at a high voltage.
A semiconductor power module package uses an insulating metal substrate (IMS) or a direct bonded copper (DBC) substrate as a supporting substrate. The DBC substrate may include a ceramic insulating layer formed of Al2O3, an upper conductive film formed of Cu arranged on an upper surface of the ceramic insulating layer, and a lower conductive film formed of Cu arranged on a lower surface of the ceramic insulating layer. The insulating metal substrate (IMS) includes a metal base member, an insulating layer disposed on the metal base member, and conductive patterns formed on the insulating layer. The IMS further includes a solder mask layer for die soldering. The solder mask layer is formed on the insulating layer to cover the entire metal patterns except portions of the metal patterns to be die-bonded or wire bonded.
In a method of fabricating a semiconductor power module package having the IMS, the IMS on which a solder mask layer is formed is prepared, a semiconductor chips are die bonded on the IMS using the solder mask layer, and the semiconductor chips and leads are wire bonded. Next, a sealing member is formed to cover the wires, and the semiconductor chips.
In the case of the semiconductor power module package having the IMS, both the solder mask layer and the sealing member are formed of an epoxy group material, and the solder mask layer directly contacts the sealing member when performing a process of forming the sealing member, and thus, an adhesion force therebetween is weak. Thus, due to the poor adhesion at an interface between the solder mask and the sealing member, an insulation breakdown voltage is reduced and an insulating characteristic is greatly reduced.